Disinfection byproducts
HAA5 in U.S. tap water
377 public water systems across 44 U.S. states report HAA5 in their annual Consumer Confidence Report. 17 sit at or above the federal limit.
377
systems measuring
17
over the limit
44
states represented
What it is
Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.
Why it's regulated
Long-term exposure above the federal limit is associated with an increased cancer risk.
Federal limit0.06 mg/L· MCL
At or above the federal limit (17)
| Water system | Measured | vs. limit |
|---|---|---|
| Albuquerque, NM 2024 annual report | 16.6 | 34.6× the limit |
| Columbus, OH 2025 annual report | 2025 ug/L | 33.8× the limit |
| Hollywood, FL 2024 annual report | 2024 ug/L | 33.7× the limit |
| Mcallen, TX 2024 annual report | 2024 ug/L | 33.7× the limit |
| Ontario, CA 2024 annual report | 13 ug/L | 6.5× the limit |
| City of Hialeah, FL 2023 annual report | 44–81 ug/L | 1.4× the limit |
| City of Homestead, FL 2023 annual report | 44–81 ug/L | 1.4× the limit |
| City of North Miami Beach, FL 2023 annual report | 44–81 ug/L | 1.4× the limit |
| Miami Dade, FL 2023 annual report | 44–81 ug/L | 1.4× the limit |
| High Point, NC 2024 annual report | 78 ug/L | 1.3× the limit |
| Springfield, MA 2024 annual report | 43–71 ug/L | 1.2× the limit |
| Brophytown Distribution System, MD 2024 annual report | 36.5–68.1 ug/L | 1.1× the limit |
| Billings, MT 2024 annual report | 17–66 ug/L | 1.1× the limit |
| Columbia, SC 2024 annual report | 11–65 | 1.1× the limit |
| Freedom District, MD 2024 annual report | 22–64.6 ug/L | 1.1× the limit |
| Brunswick, MD 2024 annual report | 22.22–63.66 ug/L | 1.1× the limit |
| Coral Springs, FL 2024 annual report | 0.29–61 ug/L | 1.0× the limit |
Approaching the limit (27)
| Water system | Measured | vs. limit |
|---|---|---|
| Columbus, GA 2024 annual report | 27–59 | 1.0× the limit |
| Akron, OH 2024 annual report | 30.9–55.1 ug/L | 0.9× the limit |
| City of Baltimore, MD 2024 annual report | 54 | 0.9× the limit |
| Stamford, CT 2024 annual report | 51 ug/L | 0.8× the limit |
| Alameda, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Albany, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Berkeley, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Castro Valley, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Crockett, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| El Cerrito, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| El Sobrante, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Emeryville, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Hayward, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Hercules, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Kensington, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Lafayette, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Moraga, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Oakland, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Orinda, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Piedmont, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Pinole, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Richmond, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Rodeo, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| San Leandro, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| San Lorenzo, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| San Pablo, CA 2024 annual report | 50 ug/L | 0.8× the limit |
| Bend, OR 2025 annual report | 12 | 0.8× the limit |
Within the federal limit (254)
| Water system | Measured |
|---|---|
| Allentown, PA 2024 annual report | 0–47.1 ug/L |
| Ventura, CA 2023 annual report | 46.8 ug/L |
| Grand Rapids, MI 2025 annual report | 46.7 ug/L |
| Orlando, FL 2024 annual report | 9.66–45.07 ug/L |
| City of Cumberland, MD 2024 annual report | 45 ug/L |
| Eastern Region Allegany Distrib System, MD 2024 annual report | 45 ug/L |
| Bridgeport, CT 2024 annual report | 43 ug/L |
| Philadelphia, PA 2023 annual report | 43 |
| Saint Paul, MN 2024 annual report | 16.1–43 ug/L |
| Atlanta, GA 2024 annual report | 15.4–42 ug/L |
| San Francisco SFPUC, CA 2023 annual report | 42 ug/L |
| Ansonia, CT 2024 annual report | 30–40.7 |
| Bethany, CT 2024 annual report | 30–40.7 |
| Branford, CT 2024 annual report | 30–40.7 |
| Cheshire, CT 2024 annual report | 30–40.7 |
| Derby, CT 2024 annual report | 30–40.7 |
| East Haven, CT 2024 annual report | 30–40.7 |
| Hamden, CT 2024 annual report | 30–40.7 |
| Milford, CT 2024 annual report | 30–40.7 |
| New Haven, CT 2024 annual report | 30–40.7 |
| North Haven, CT 2024 annual report | 30–40.7 |
| Orange, CT 2024 annual report | 30–40.7 |
| Seymour, CT 2024 annual report | 30–40.7 |
| West Haven, CT 2024 annual report | 30–40.7 |
| Woodbridge, CT 2024 annual report | 30–40.7 |
| Bakersfield, CA 2024 annual report | 40 ug/L |
| San Mateo, CA 2024 annual report | 40 ug/L |
| New Bedford, MA 2024 annual report | 39.8 ug/L |
| Mesquite, TX 2024 annual report | 10–39 ug/L |
| Minneapolis, MN 2023 annual report | 1–39 |
| Newark, NJ 2024 annual report | 39 ug/L |
| Suffolk, VA 2024 annual report | 39 ug/L |
| Keswick Multi Care Center, MD 2024 annual report | 40–37.8 ug/L |
| Sunnyvale, CA 2024 annual report | 37.5 ug/L |
| Wichita Falls, TX 2024 annual report | 8.4–37.4 |
| Jersey City, NJ 2024 annual report | 37.2 ug/L |
| Daly City, CA 2024 annual report | 37 ug/L |
| Washington Dc, DC 2023 annual report | 37 ug/L |
| Jacksonville, FL 2024 annual report | 5.1–36.85 ug/L |
| Calverton School, MD 2024 annual report | 36 ug/L |
| Lakeland, FL 2024 annual report | 10.6–36 ug/L |
| Oklahoma City, OK 2024 annual report | 36 ug/L |
| St Louis, MO 2024 annual report | 7.6–36 ug/L |
| City of Cupertino, CA 2024 annual report | 35.8 ug/L |
| San Jose, CA 2024 annual report | 35.8 ug/L |
| Fort Lauderdale, FL 2024 annual report | 14.1–35.5 ug/L |
| Hartford, CT 2024 annual report | 35.5 ug/L |
| Santa Clara, CA 2024 annual report | 34.9 ug/L |
| Naperville, IL 2024 annual report | 11.8–34.6 ug/L |
| Mobile, AL 2024 annual report | 6.6–34.5 |
Showing 50 of 254. The full list is in the JSON API.
Frequently asked
+What is HAA5?
Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. Long-term exposure above the federal limit is associated with an increased cancer risk.
+What is the federal limit for HAA5 in drinking water?
The federal MCL for HAA5 is 0.06 mg/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have HAA5 over the federal limit?
17 of the 377 public water systems on The Water Map report HAA5 at or above its federal limit, spanning 44 U.S. states. The full list is on this page.
+How can I check if HAA5 is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including HAA5.